• Otávio Santiago

Gut Microbiome Affected by Genetics More Than Once Thought

Our gut microbiome is primarily affected by our lifestyle, including what we eat or the medications we take, most studies show. But a new study (“Gut microbiome heritability is nearly universal but environmentally contingent”) in Science, reports a much greater genetic component at play than was once known.

In the study, researchers discovered that most bacteria in the gut microbiome are heritable after looking at more than 16,000 gut microbiome profiles collected over 14 years from a long-studied population of baboons in Kenya’s Amboseli National Park. However, this heritability changes over time, across seasons and with age. The team also found that several of the microbiome traits heritable in baboons are also heritable in humans.

“Relatives have more similar gut microbiomes than nonrelatives, but the degree to which this similarity results from shared genotypes versus shared environments has been controversial. Here, we leveraged 16,234 gut microbiome profiles, collected over 14 years from 585 wild baboons, to reveal that host genetic effects on the gut microbiome are nearly universal. Controlling for diet, age, and socioecological variation, 97% of microbiome phenotypes were significantly heritable, including several reported as heritable in humans. Heritability was typically low (mean = 0.068) but was systematically greater in the dry season, with low diet diversity, and in older hosts,” write the investigators.

“We show that longitudinal profiles and large sample sizes are crucial to quantifying microbiome heritability, and indicate scope for selection on microbiome characteristics as a host phenotype.”

“The environment plays a bigger role in shaping the microbiome than your genes, but what this study does is move us away from the idea that genes play very little role in the microbiome to the idea that genes play a pervasive, if small, role,” said Elizabeth Archie, PhD, professor in the department of biological Sciences at the University of Notre Dame and a principal investigator on the study who is also affiliated with the Eck Institute for Global Health and the Environmental Change Initiative.

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